1. Field of Invention
The present invention relates to a strap-tensioning apparatus for tying down cargo on a vehicle and, more particularly, to a strap-tensioning apparatus capable of avoiding excessively fast withdrawal of a strap.
2. Related Prior Art
Referring to FIGS. 1 through 3, a conventional strap-tensioning apparatus includes a base 10, a handle 11, a reel 12, an axle 13 for connecting the handle 11 and the reel 12 to the base 10, and a rod 14 secured to the base 10. A short strap 15 is tied to the rod 14. A long strap 20 is wound on the reel 12. The reel 12 is formed with two ratcheted wheels 17. A suppressor 16 is elastically supported on the base 10 and in elastic contact with the ratcheted wheels 17. The base 10 is formed with two bosses 18. The handle 11 includes an opening 22 defined therein and two cams formed thereon. A detent 19 is elastically connected to the handle 11 while another detent 23 is elastically supported on the base 10.
As shown in FIG. 1, the handle 11 is pivoted to a releasing position relative to the base 10. The detent 19 is kept away from the ratcheted wheels 17 of the reel 12 by the bosses 18. The detent 23 is kept away from the ratcheted wheels 17 of the reel 12 by the cams of the handle 11. The suppressor 16 is in elastic contact with the ratcheted wheels 17. The reeling in of the long strap 20 is avoided. However, the long strap 20 can be manually reeled out as indicated by an arrow head 21. During the reeling of the long strap 20, the ratcheted wheels 17 hit the suppressor 16 and make click sounds.
As shown in FIG. 2, the detent 19 is pressed down by a finger or a tool inserted through the opening 22. An end of the suppressor 16 is moved by the detent 19 while another end of the suppressor 16 is removed from the ratcheted wheels 17. Hence, the reel 12 is free for spinning. Accordingly, the long strap 20 can be reeled in as indicated by an arrow head.
As shown in FIG. 3, the handle 11 is manually pivoted to and fro to reel in the long strap 20. As the handle 11 is pivoted clockwise, the detent 19 engages with and spins the ratcheted wheels 17 while the detent 23 rattles and slides on the ratcheted wheels 17 so that the long strap 20 is reeled in. As the handle 11 is pivoted counterclockwise, the detent 19 rattles and slides on the ratcheted wheels 17 while the detent 23 engages with and bosses 18 the ratcheted wheels 17 so that the long strap 20 is not reeled out.
The long strap 20 can be automatically reeled in as shown in FIG. 2. The automatic reeling in of the long strap 20 could be excessively fast so that the long strap 20 could be turned into a whip that could hurt people. The situation could be worse since the free end of the long strap 20 is often connected to a hook that would cause more damages.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.